British Standard 6580
"...The use of D15 standards, already called out by U.S. regulators as a minimum for a quality product that will help protect an engine, has recently expanded further. The BTC Engine Coolants Technical Committee, part of the BTC Testing Advisory Group headquartered in Leicestershire, England, has adopted eight standards of D15’s standards. These standards, now referenced in British Standard 6580, Specification for Corrosion Inhibiting, Engine Coolant Concentrates, describe coolant attributes, from freezing point to boiling point and corrosion to foaming...."
See full description: ASTM International - Standards Worldwide


My interpretation of the above is that all USA antifreeze are required to meet the D-15 Standard and within the D-15 Standard is the British Standard 6580. So for my '93 XJS, ZEREX, G-05, phosphate free, and low Ph, meets the Jaguar specifications (See fifth posting up)

 

Back when I had the XJS V12, my research lead me to choose the Xerex G-05 as the ideal coolant for it. I've also used it in the TR8 V8, a Land Rover V8, and and XJ8.

 

I am about to change out the timing gear, and in the process will be flushing and replacing my coolant. My car is a 2001 XJ8 which clearly calls for WSS M97B44-D on the reservoir tank.

My dilemma:

The engine is a 99 model (990323 0632) which I'm afraid may fall before the switch from DOW D542. Since they do the switch based on VIN number and not engine number I'm not sure how to proceed. I don't know the VIN number from the car the engine came from.

I presume I should use coolant based on the engine and not the car?

The person who installed the engine apparently followed the label on the reservoir. The current coolant appears to be orange.

Any advice?

 

I MAY have just found my answer. According to an amended TSB (303-11) I found you can apparently use the newer coolant in the older systems as long as they are fully flushed first. I would still appreciate any confirmation though if anyone has a clearer understanding of this. Thanks.

 

Yeah, I would THINK the engine and peripheral equipment did not change, only the coolant.

 

Your thinking is correct, go for the new coolant.